Method of Controlling Common Rail Fuel Injection Device

Abstract

A method for controlling a common-rail fuel injection system, which avoids the adverse effect of the pilot injection on the main injection while driving an engine and maximizes the cleaning up of the exhaust gas by the pilot injection or the like, is provided. In the common-rail fuel injection system performing a multistage injection, a pilot injection timing θp at a crankshaft angle and a main injection timing θm at the crankshaft angle base are controlled by a ECU. The ECU calculates a pilot injection interval Tpin at a time base and adjusts the main injection timing θm when the pilot injection interval Tpin is less than the predefined threshold (1 (ms) in the present embodiment).

1 . A method for controlling a common-rail fuel injection system, controlling a pilot injection timing based on crankshaft angle and a main injection timing based on crankshaft angle by a controller, in the common-rail fuel injection system which performs a multistage injection, comprising the step of:
 calculating a pilot injection interval at a time base by the controller, and   adjusting the main injection timing based on crankshaft angle, so as to secure the pilot injection interval at the time base, when the pilot injection interval is less than the predefined threshold.   
   
   
       2 . The method for controlling the common-rail fuel injection system as set forth in  claim 1 , wherein the pilot injection interval at the time base is calculated and output by the controller, based on the pilot injection timing based on crankshaft angle, the main injection timing based on crankshaft angle and an engine rotation number at a calculating time. 
   
   
       3 . The method for controlling the common-rail fuel injection system as set forth in  claim 1 , wherein a correction main injection timing at a time base is adopted as the main injection timing, by adjusting so as to delay by the time with a combination of the pilot injection time and the pilot injection interval at the time base, going by the pilot injection timing based on crankshaft angle, based on the pilot injection timing based on crankshaft angle, the pilot injection time and the pilot injection interval at the time base.